The invention relates to a device for the conveyance of material, in particular bulk material, comprising at least one trough-type conveyor element with a cyclical drive for transmitting a propelling force periodically to the material present in the trough-type conveyor element at least in the envisaged direction of conveyance.
Such a device is known as the so-called vibrating trough or throwing trough. In the case of a vibrating or throwing trough, the trough-type conveyor element is set up essentially horizontally. The trough-type element is driven cyclically both in the vertical and in the horizontal direction, so that the material to be conveyed gains acceleration in both the vertical and the horizontal direction in the trough-type element. The material is thereby conveyed in the horizontal direction through the trough-type conveyor element. In order to increase the conveyance speed of a vibrating trough, the vertical trough acceleration is increased to above the acceleration of gravity, which produces a so-called throwing trough, in which the maximum vertical acceleration is in practice about three times the acceleration of gravity.
The known vibrating and throwing troughs have, however, a number of disadvantages. The conveyance of the material can take place only virtually horizontally, with the speed of conveyance being relatively low. Although in throwing troughs the speed of conveyance is somewhat higher, the greater accelerations give rise to collision forces between the trough and the material, and fluidization occurs, which has an adverse effect on the speed of conveyance. Vertical accelerations which are greater than about three times the acceleration of gravity also give an insufficient increase in the only low horizontal speed of conveyance. The virtually horizontal propelling force occurs in throwing troughs only during the brief contact times (collision time) between the material and the trough, in which case the chance of damage due to the collision forces occurring is relatively great.